Electric switch box



Jan. 4, 1938.

J. c. RICHARDSON 2,104,167

ELECTRIC SEJL'ICI E BOX Filed May 8, 1936 4 Sheeets-Sheet l INVENTOR.

Jan. 4, 1938.

J. C. RICHARDSON ELECTRIC SWITCH BOX Filed May 8, 195s 4 Sheets-Sheet 2 Q IIIIIIIIIIIIiiIiii 1938- J. c. RICHARDSON 2,104,167

ELECTRIC SWITCH BOX Filed May 8,. 1936 4 Sheets- Sheet 3 1 VENTOR. Ja/fies 6.2 1 C770ICZ5OIL,

Jan. 4, 1938. J. c. RICHARDSON 2,104,167

ELECTRIC SWITCH BOX Filed May 8, 1936 4 Sheets-Sheet 4 SE/YL/NG WQX INVENTOR' Patented Jan. 4, 1938 UNITED STATES PATENT OFFICE ELECTRIC SWITCH BOX Application May 8, 1036, Serial No. '18,"!

Claims.

This invention relates to electric switch boxes and to a circuit breaking switch used in connection therewith. An obiect of the invention is to provide a box or enclosure having a cover for 5 an electric switch with a handle outside the box for operating the switch and an interlock between the switch operating mechanism and the cover whereby the switch cannot be closed until the cover is closed and whereby the cover cannot be 1 opened until the switch has been opened. Another obiect of the invention is to provide a latching member for the cover of the box operated by a disc associated with the switch operating mechanisin; another object of the invention is to provide 1 a pivoted latch for the cover of the box with a second latch pivoted to the first latch for controlling the switch operating mechanism. Another object of the invention is to provide a gravity latch for the cover of the box which is automatically moved into the latching position as the cover is closed. Another object oi the invention is to provide a switch member spaced from a pair ofcontact members with a barrieroi insulation between the switch member and each 0! the contact members,

said barriers being rotatably mounted and carrying contact members to establish the circuit. Another object of the invention is to provide means for mounting electric terminal members on a base of insulation by a bolt attachment with the bolt head or nut placed in an enlarged aperture on the underside of the base and having a sealing compound closing the aperture, with means for separating the sealing compound from the bolt. Other objects of the invention will be more particularly understood from the following specifications and the accompanying drawings, in which,

' Fig. 1 is a plan view of a switch box with the cover open showing my invention;

9 Fig. 2 is an elevation of the interlocking mechanism between the cover and the switch operating mechanism, the switch operating rod being shown in section;

Fig. 3 is a view of the mechanism shown in Fig.

2, with the door latched and the switch closed:

Fig. 4 shows the interlocking mechanism locking the switch against the closing movement;

Fig. 5 is a cross section on line l--l,1"lg. 4;

Fig. 6 is a side elevation of the switch box showso ing the operating handle;

' Fig; 'i is a front view of the gravity latch Fig. 8 is a side view of the gravity latch with the latch member sectioned on line H of Fig. 7, and

u Hg.9isasectiononlinellof1'ig.7.

Fig. 10 is a plan view of the switch blade, the contact members and the barrier;

Fig. 11 is an elevation on line ii-i I of Fig. 10; Fig. 12 is a side elevation corresponding to Fig. 11, with the barriers in the open switch position; 5

Fig. 13 is an end view 01' Fig. 10, from the right;

Fig. 14 is a cross section of the barrier member showing the contact plates mounted thereon;

F18. 15 is a vertical section of the base and terminal with the attaching bolt and the seal, and 10 Fig. 16 is a detail used in Fig. 15.

The electric service for a building is usually controlled by switches placed in a box and 0perated by a handle outside the box. It is necessary at times to get access to the switches for 15 replacing fuses and the like and in order that the electric supply may be cut oil before the fuse terminals. are accessible, an interlock is provided between the switch operating mechanism and the cover 0! the box so that the box cannot be opened 20 until the switch is first opened and after the been opened the switch cannot again be closed until the cover is closed and latched. For this purpose the switch operating handle rotates a disc inside the box which is connected with an 25 operating crank through a lost motion connection, and this crank, in turn, rotates the barrier members to open, or to close the switch, depending upon the direction in which it is rotated. A spring is connected with the crank to form a 30 toggle so that as the crank is moved over the toggle center in either direction, the lost motion permits it to complete its movement with a snap, thereby producing a snap action for closing and for opening the switch. 5

A compound latch member is pivoted to the side of the boxand is normally urged by a spring into the latching P litico but is released from this podtion by a cam on the disc when the switch is placed in the open position thus releasing the so cover. The second latch member is held in the latching position by the same spring that up crates the main latching member and normally stands in position to engage a cleat on the disc and thereby prevent its rotation to the switch 4,5 closing position. When the cover is closed the latching cleat oi the cover engages the second latch inemben'moving it into the released position and thereby enabling the switch to be closed.

A lock is provided, for the operating handle to 56 that it may be padlocked in the open position when the electric service is cut oil.

A gravity latch may be provided to secure the door to the box and which, by gravity, normally assumes the latching position, but as the doors s5 close this ,member engages an inclined plane which moves it back'from the latching position until the door is completely closed, when the latch is free to engage by gravity.

The electric circuit is controlled between a vertically mounted switch blade and a pair of spaced jaws with a barrier of insulation pivotally mounted between the switch blade and each member of the jaw. A contact blade is provided on each side of the barrier member and electrically connected so that when these members, which are rotated by the crank are in the closed position,

the contact plates bridge the gap between the switch blade and the jaws. As the barrier members are rotated the plates are withdrawn to open the circuit.

In the drawings, H is a sheet iron switch box which usually has its upper edges turned inwardly as indicated at B2 and is provided with a sheet iron cover l3 hinged at it and may be provided with the hasp, member it for the gravity latch. Slate panels it are secured to the box as indicated and are provided with the terminals i'l to which the conductors it may be attached, by any suitable form of terminal, the form indicated in the drawings corresponding with my copending application, Serial No. 51,746, filed Nov. 27, 1935. Corresponding terminals are provided at iii for the conductors 2i! and intermediate terminals are provided at 2! to support the switch blade 23 between the barriers 2d and 25 which engage the operating crank 27 at 26 and are rotated as the crank is rotated. The space between the terminals i? and 25 is used for fuses 22 which are attached by the usual'fuse clips. If fuses are not required, provision is made for attaching the conductors iii to the terminals ii. The crank 27 is bent into the crank arms 28 and its, the latter having a bearing in plate as and the arm 28 has a bearing in disc 8i. The bearing axis of the crank corresponds with the axis 38 of the barriers 2d and 255. A collar 32, on the crank 2?, is connected to the coil spring 33 which is secured to the fixed cleat 36 on the side of the box. This spring snaps the switch members into position in both directions. In order to aid the coil spring 38, leaf spring reinforced by the member 65, and spring til, secured to the pad 32 on disc at are arranged to engage the arm 28 oi the crank 27 as indicated in Figs. 2 and 3. These springs are compressed by the crank arm and give it an initial impetus to start it over the toggle as indicated by line H. The disc 38 is connected through the rotary member by the rivets fill with the handle 36 on the outside of the box so that disc 3! is rotated as the handle 38 is operated. The switch is in the closed position when this handle engages the stop il, Fig. 6, audit is open when the handle is moved into the dotted position in Fig. 6, with the lu 89 registering with the lug til, each of which are perforated to receive a padlock in this position.

The disc Si is provided with a pair of spaced lugs as and 8? which are bent forward from the stock into position to engage the crank arm 28 so that as disc 85 is rotated in the direction of the arrow, Fig. 2, the lug Q6 engages 2t and carries it around until it passes the line a-a when the spring 33 snaps the crank arm 28 through the lost motion to engage the lug all, as indicated in Fig. 3, which is the closed position of the switch. When disc ill is rotated inthe opposite direction the lug d? engages the arm 22 until the toggle center is passed when the crank 2i snaps over to engage lug 46, thereby opening the switch by snap action.

A vertical main latch member II is pivotally secured at one end at 82 to the side of the box and is provided with a latch lug 83 atthe other end which engages the hasp 84, secured to the cover 13 when the cover is closed. The second latch member 85 is pivoted at 88 to the top of the main latch member 8| and is provided with a stop 81, Fig. 5, arranged to engage 8| and limit its forward movement. This latch member is also provided with 9. lug 88 engaged by the stem 89 upon which the coil spring 88 is placed in abutting relation with lug 81 of the cleat 82 secured to the side of the box. The stem 88 holds the spring 90 in position and slides freely through the lug 9!. The spring 98, through lug 88, urges both the main and the second latching members into the latching position.

The second latching member is provided with a lug as arranged to engage the head 94 of the hasp at when the hasp is in the latching position. This moves the second latching member on its pivot 85 backwards to release the latch 85 from the cleat as, secured to disc 88, the illustration in Fig. 3 shows the second latch in the released pmition and the illustrations in Figs. 2 and 4 show this latch in the engaging position.

It will be observed from Fig. 2, that the cam on disc ill at $7, opposite cleat 86, engages the main latch 8i and moves it back from the latching position b to the unlatched position 0 thereby releasing the hasp 8d and permitting the door to be opened. The switches are open in this position When the disc 3i isrotated to the position indicated in Fig. 4, ti is released from the cam 9? and the cleat 88 engages the ledge at 95 on the second latch member 85, thereby preventing the movement of the crank 21 over the toggle position a and preventing the switches from being closed. This looks the switches in the open position as long as the cover remains open.

When the cover is closed, the hasp 88, Fig. 3, engages the lug 95, of the second latch 85 at 94, that is, when the beep engages the lug 83 of the main latch. This moves the second latch to the released position as indicated in Fig. 3, so that the disc 3i is not retarded in its rotation by the cleat 9t engaging 95 and thus the crank 21 is rotated to close the switch. When the switch is closed, the door remains latched and cannot be unlatched until the disc 3! is brought into position as appears in Fig. 2, which moves the latch 82 from the position b to the position 0. It will be observed that the lug 88, which receives the thrust of the spring 96 is close to the pivot 86, while it is at the opposite end from the pivot 82 of latch ill. The result is that latch 85 is moved to the unlatching position indicated in Fig. 3, with only a slight additional compression of the spring, while the movement of latch 8! from. the latched to the unlatched position requires considerable compression of this spring, the result is that in moving the latch 85 into the unlatchcd position the pressure of the spring is not released on the main latch 8! which remains in the latching position.

It will be observed that it is the engagement between the hasp 84 and the main latch at 88 that releases the second latch 85 to permit the switch to be closed. The switch box must be latched before the switch operating handle is released. Owing to the independent pivotal mounting of each latch, should the hasp due to wear or other causes fail to release the second latch, it would, nevertheless engage the main latch and hold the cover closed.

The gravity latch, Figs. '7, 8 and 9, for automatically latching the door as it is closed, comprises the latch member I02, pivoted to the door at IOI and restricted in its outward movement by the stop I03. This latched member has a lug I04 which passes through a hasp I5, secured to the body of the box and having an end I01 bent at a right angle towards the latching member I06 and formed in an inclined plane as indicated in Fig. 9. The latched member I02 is weighted at I06 by an increase in the width of the stock, so that, by gravity, when the box is in the ,vertical position, it assumes the position shown in Fig. 7. When the cover I3 is moved to the closed position, the edge I08 of the latching member I06 engages the inclined plane I0I, which forces the latch back so that the lug I04 clears the hasp I5 and when the door is fully closed the member I06 moves freely in the slot I09 below the member I01 to the latching position shown where it may be secured by the padlock I05.

The contact member of the switch will be un-- derstood from Figs. 10 to 14, in which Si is the base of insulation upon which the terminal 52 is secured, having the clips 53 to receive the fuse plug and supporting the vertical switch blade 54. The terminal 58 is also secured to the panel 51 and has secured thereto the upstanding contact members 55 and 56 which carry the pivot member 53 for the insulated barriers 6i and 62 which engage the crank member 64 through a slot as indicated in Fig. 11. The barriers are provided with a slot at 65 through which the sheet metal contact member is inserted and bent parallel with the barrier as indicated at 66 and 61, Fig. 14. The contact plates 66 and 81 bridge the gap between the knife blade 54 and the jaw member 55 on one side and the jaw member 56 on the opposite side, thus providing a double contact member for the circuit having a considerable area in contact. When the barriers are rotated on the axis 63 by the crank 64, the contact plates are removed from the contacting position as indicated in Fig. 11, to the position indicated in Fig. 12, thus interposing a barrier of insulation between the knife blade 54 and the contacting members 55 and 56. Through the clamp 60 and the jaw 59 a conductor may be secured to the terminal 58.

In Fig. 15, the terminal 52 is secured to the base 5I by the screw II, engaging the nut- T3 in the aperture I2 which is open from the underside of the base 5| which adjoins the bottom 05 the metal box I0. It is necessary to close the aperture 12 by a sealing compound I5 of insulation. It has been found that when this compound is poured hot into the aperture over the bolt and the nut, that it has the tendency to crack and become loose and permit moisture between the bolt and the bottom of the box. This condition is considerably aggravated as the bolt is screwed or unscrewed into position after the sealing compound has set. In order to prevent this condition, I provide a metal cap I4, Fig. 16 for protecting the nut and leaving sufiicient freedom for the movement of the end of the bolt without applying any strain to the compound which is poured into the aperture on the top of the cap, the cap being located between the compound and the bolt.

This invention may be applied complete as illus trated in the various drawings or its separate elements may be used with other types of switches without departing from the intent and spirit of the invention.

Having thus described my invention, I claim:

1. An interlock for an electric switch box comprising a box with a cover having a hasp, an electric switch located in said box having an open ating mechanism, a handle outside said box for operating said mechanism, a main latch pivoted at one end to said box and engaging said hasp at the other end to hold the cover closed, a second latch pivoted to said main latch and locking said mechanism against movement to close the switch, and a spring normally forcing said latches into the engaging position.

2. An interlock for an electric switch box comprising a box with a cover having a hasp, an electric switch in said box having an operating mechanism including a locking member, a handle out" side said box for operating said mechanism, a maln latch pivoted to said box having a lug engaging said hasp to lock said cover in the closed position, a second latch pivoted to said main latch and engaging said locking member and means for releasing said second latch by said hasp.

3. An interlock for an electric switch box 30m prising a box with a cover having a hasp, an elee-= tric switch in said box having an operating mechanism including a locking member, a handle outside said box for operating said mechanism, a main latch pivoted at one end to said box having a lug at the opposite end engaging said hasp to lock said cover in the closed position, a second latch pivoted to said main latch and engaging said locking member, said locking member releasing said main latch when the switch is open and being in position to be engaged by second latch when the switch is open.

1. An interlock for an electric switch com prising a box with a cover having a hasp, an electric switch in said box having an operating mechanism including a locking member, a handle out side said box for operating said mechanism, a main latch pivoted to said box having a lug em gagihg said hasp to lock said cover in the closed position, a second latch pivoted to said main latch and engaging said locking member, said locking member releasing said main latch when the switch is open and a spring engaging said second latch to force both latches into the latching posi tion.

cl: an electric switch box COlli th a cover having a hasp, an elecsaid mechanism, a to sa d box and engaging said second latch .iavl lug to hold th pivoted to the free end oengaging said locking inenib open and a spring for forcin, engaging position.

6. An interlock for an electric mite. Y prising a box with a cover having electric switch in said box having opera mechanism including rotating locking member, a handle outside said box for operating said l the switch iatches into the mechanism, a main latch pivoted at one to said box and having a lug at its free end ond latch engaging said hasp to release the locking member when the cover is in closed position.

7. An interlock for an electric switch box comprising a box with a cover having a hasp, an electric switch in said box having an operating mechanism including a rotating locking member, a handle outside said box for operating said mechanism, a main latch pivoted at one end to said box and having a lug at its free end engaging said hasp to hold the coverclosed, a second latch pivoted to said main latch at its free end and engaging said locking member when the switch is in open position, a spring engaging said second latch close to its pivot to force both latches into the engaging position and means for releasing the second latch by said hasp when the cover is in closed position.

8. An electric switch box having a pivoted disc controlling member for controlling the circuit, a crank engaging said disc to rotate said disc from the closed to the open position and vice versa, a disc member having spaced lugs engaging an arm of said crank with a lost motion, a pair of opposed springs secured to said disc member, one of said pair of springs engaging the crank arm before it engages the lug in each direction of movement, a spring forming a toggle to move said crank through the lost motion, a handle outside said box for operating said disc and means for locking said disc against movement in a direction that will close the switch.

9. An electric switch comprising a terminal connecting to a conductor and having a pair of spaced spring contact members connected to said terminal mounted on a base, a switch blade fixed and spaced between said contact members and a pair of rotary switch members, each comprising a disc of insulation with a contact member on each side of each disc, one of said members rotating between the switch blade and one of said spring contact members and the other member rotating between the blade and the other spring contact member and means for rotating said discs together to open and close the circuit with a snap action.

10. An electric switch comprising a base having a pair of upstanding clips spaced from each other, a switch blade fixed and spaced between said clips, 8. pair of discs of insulation pivotally mounted on said pair of clips and one rotating in the space between the switch blade and one of the clips and the other rotating between the switch blade and the other clip, a contact memher on each side of each disc and electrically connected through said disc for establishing the circuit between the switch blade and each of said clips when the switch is closed and means for rotating said discs together, said contact menibers being arranged to make and interrupt the circuit at the same time.

11. In an electric switch panel, the combination, a panel of insulation having a counterbored hole in the back with a nut therein, a switch fitting on the face of the panel, a screw engaging said fitting and securing said fitting to-the face of the panel by said nut, a. cap placed adjacent said nut for securing a free space at the end of the screw as it passes through the nut and sealing compound for securing said cap and nut in the counterbored hole.

12. In an electric switch panel, the combination, a panel of insulation having a counterbored hole in the back with a nut therein, a switch fitting on the face of said panel, a screw securing said fitting to the face of said panel by screwing into said nut, an insulating sealing compound for said hole and ,nut applied from the back of said panel and means for keeping the sealing compound spaced from the end of the screw.

13. An interlock for an electric switch box comprising a box with a cover having a, hasp, an electric switch located in said box having an operating mechanism, a handle outside said box for operating said mechanism, a main latch pivoted at one end to said box engaging said hasp to hold the cover closed, a second latch pivoted at its end to said main latch and locking said switch mechanism and a spring normally forcing said latches into the engaging position and applying a greater tension to one latch than the other.

14. A gravity lock for an electric switch box comprising a box with a hinged cover, an upstanding hasp secured to said box and a slot in the cover to admit the hasp when the cover is closed, one part of said hasp being bent at a right angle to the side of the box and formed on an inclined plane and spaced from the cover when it is closed, a. latch member pivoted to the door and weighted to assume a vertical position and having a hook end, said latch member engaging the inclined plane of the hasp to withdraw the hook clear of the hasp and a slot in the hasp for receiving the latch member as it moves on its pivot. by gravity in the space below the right angle part when the door closes.

' JAMES C. RICHARDSON. 

